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Sept. 11, 1962
D. SHICHMAN
3,053,610
FLAME-SPRAYED METAL ARTICLE
Original Filed March 18, 1957
IN VEN TOR .
DAN/£1 JW/C/IMA/V
.A 1‘ TORNEY
United States Patent O?lice
3,053,610
Patented Sept. 11, 1962
1
2
3,053,610
molds can be increased to such a high degree ‘as to allow
their use under conditions of high stress, as in compres
FLAME-SPRAYED METAL ARTICLE
sion molding, with accurate reproduction of all surface
Daniel Shichman, Cedar Grove, N.J., assignor to United
States Rubber Company, New York, N.Y., a corpora
tion of New Jersey
Original application Mar. 18, 1957, Ser. No. 646,662, now
Patent No. 2,966,423, dated Dec. 27, 1960. Divided
and this application June 9, 1960, Ser. No. 34,928
6 Claims. (Cl. 18--47)
detail of the model, if the article or mold is composed
of layers of selected metals deposited in a certain manner
and subsequently heat treated at certain temperatures.
My invention accordingly comprises a method of pro
ducing a strong, ductile, ?ame-sprayed metal coating or
object, comprised of spraying simultaneously a plurality
10 of metals having widely different melting points, one of
This invention relates to the production of sprayed
metal articles, particularly molds or the like useful in
which metals is a self-?uxing brazing alloy, onto the
same area of a surface until a deposit of the desired thick
ness has been built up, and thereafter sintering the object
the compression molding of plastics such as synthetic
or coating at or above the melting point of the lower
resins, rubber, etc. It also relates to an improved method
of metalizing. It further relates to improvements in the 15 melting, brazing alloy but at ‘a temperature lower than
the melting point of any of the higher-melting metals.
?ame-spraying of high-melting metals onto smooth sur
faces of a model whereby the metal is made to adhere
A mold, or any thick article, produced by my method is
not brittle, its shrinkage is negligible, and it does not crack
to smooth surfaces without bouncing oif and wherein all
no matter how thick it is. By this method I am able to
surface detail of the model is accurately and faithfully
reproduced in the adjacent surface of the deposited metal. 20 produce articles in which the sprayed metal parts ‘are
characterized by great toughness and very high tensile
Molds which are used under presses, as in compres
sion molding, generally are strong enough to withstand ‘ strength.
In accordance with the practice of my invention, a thin
compressive stresses up to at least 5,000 p.s.i., they have
a hardness on the order of 30 on the Rockwell C scale,
base layer of hard metal is built up on a model by spray
and, if used in molding rubber articles, they are able to 25 ing the hard metal onto a silicate-coated model; then a
backing layer is spray-deposited over the hard metal by
withstand temperatures above 650° F. and are inert to
the simultaneous spraying of two or more metals, one of
rubber. Present methods of making these articles and
which is a self-?uxing brazing alloy, to the desired thick
molds involve cutting or etching a hard metal block and
ness. Upon being sintered or heat treated at a tempera
the like. This is expensive, especially if the mold is to
be used in making only a small number of articles, as 30 ture above the melting point of the lowest-melting metal,
viz., the brazing alloy, but below that of the base layer
for samples.
metal and below that of the high-melting metal in the
v‘Flame-sprayed metal molds and articles made by prior
methods, as the one described in Hugger, 2,629,907, are
backing layer, the high-melting metal particles cohere
strongly and the low-melting ?ller metal flows into the
much cheaper to make, and it is possible to obtain good
surface detail from a model made of cheap material, such 35 interstices of the non-melted particles, whereby, upon
cooling, a metallurgical bond of high strength is produced.
as plaster of Paris. In these methods a metal deposit is
Heretofore, it has been difficult to spray onto a smooth
built up on an adhesive-coated model by spraying the
model a base layer of relatively hard metal having a
model with molten particles of metal which on cooling
spraying temperature of from above ll00° to as high as
solidify. A soft metal of low melting point, e.g., alumi
num, is generally used as the sprayed metal, since the 40 1850° F. I have found that this can be done easily and
conveniently by spraying such hard metal onto a thin,
known adhesives for collecting the sprayed metal have ‘ dried coating of a ?lm-forming silicate such as sodium
been incapable of performing satisfactorily at the tem
silicate which has previously been deposited on the model
peratures, considerably above 1200° F., at which hard
metals must be sprayed-—usually above 1750° F. As a
result, molds when made by prior sprayed-metal methods 45
from an aqueous solution thereof.
The term “self-?uxing brazing alloy” is well under
are brittle, are liable to crack, and may break under , r; stood in the industry to signify a brazing alloy which
of itself performs the fluXing function of removing sur
stresses above 5,000 p.s.i. This limits their use to non
face oxides and other undesirable substances during
pressure molding, such as slush molding.
brazing. Satisfactory performance of the self-?uxing
The process generally known as metalizing is widely
used in the metal-working industry for the purpose of 50 function usually requires the inclusion of a strong de
repairing or re-conditioning worn metal parts, such ‘as ,5; oxidizer such as phosphorous, lithium, boron, cadmium
or tin in the brazing alloy.
shafts and mill rolls which are to be restored to their
In the accompanying drawing forming a part of the
original dimensions. Metalizing may also be applied to
disclosure:
ceramic and other articles. Metalizing is done by ?ame
FIG. 1 is a perspective view of a laminated section of
spray techniques. The surfaces on which new metal is 55
to be deposited are ?rst roughened, if necessary, then .1. a mold for a golf ball, formed in accordance with my
sprayed with the desired metal, usually steel, until the
invention; and
'
FIG. 2 is an elevational view illustrating a sprayed
deposit has been built up to the desired thickness. The
metal mold deposited over a model and showing parts
new surfaces of the built-up parts may then be machined
or ground to the required dimensions. In this process 60 broken away, together with apparatus for producing the
article.
.
there is no particular problem of adhesion of the added
In the drawing, an article made according to this in
metal to the deposition surface. But the lower strength
and lack of toughness of the added metal leave much to
vention is shown as a mold section, or half-mold, 1, for
producing golf balls, comprising an inner or base layer
be desired in prior processes.
It is well known that, in order to strongly bond two 65 2 of hard metal and an outer or backing layer 3 of several
metals. The metals are selected and deposited in the
metals together, as in brazing, surface oxides and other
undesirable substances must be removed in order to per
manner to be described herein.
As shown, the apparatus for carrying out the inven
mit wetting of the base metal by the molten ?ller metal.
tion comprises a suitably mounted stand 11, rotatably
This ?uxing function may be performed by a separate
?ux or by a self-?uxing brazing alloy
70 supporting a hub 12' into which is screwed a bolt 13
embedded in the plaster model 4. A layer of adhesive
My invention lies in part in my discovery that the
5, a base layer 2 of met-a1 and a backing layer 3 of two
ductility and toughness of sprayed metal articles and
3,053,610
4
In the next step, the base layer 2 is backed with a
layer 3 of a plurality of metals, for example, a combina
tion of (a) a Phosphor~bronze having the composition
94.75% copper, 5% tin and 0.25% phosphorus, and
or more metals cover the model 4. A spray gun 3‘ with
fuel lines 14, which is conventional, is utilized to spray
the adhesive 5‘ and molten metal particles onto the model
4. The metals are fed into the gun 8 in wire form
9,, as shown, or in powder form. Duct 10‘ provides a
means of supplying hot and cold air to the model dur
(b) a self-fluxing silver brazing alloy containing 80%
copper, 15 % silver and 5% phosphorus, by simultaneous
?ame-spraying of both alloys as molten particles. The
preferred way of doing this is to feed the metals together
ing the spraying, as required, from a source not con
sidered a part of this invention.
through the same ?ame gun 8 in either powdered or wire
In an illustrative embodiment of my invention a model
4 [is screwed into the hub 12 of stand 11, and a thin 10 form 9. Wires of several metals can be fed into the gun
by combining them into one wire, as by making a con
layer 5 of an aqueous solution of sodium silicate is
centric multi-layered wire in which the core is of one
sprayed over the model, while it is being rotated by hub
metal, e.g., a self-?uxing silver brazing alloy, and the
12 and pulley 15 driven by a motor which is not shown,
outer layers are of other metals, as Phosphor-bronze, or
to a sufficient thickness to provide a means for parting
the ‘model 4 from the metal shell 1 which is to be de 15 by entwining strands of the various metals into one wire
of a size which will fit the ?ame gun. Where the metals
posited over it, but not so thick as to obliterate surface
are in powdered form, the powders can be intermixed and
detail on the model and prevent its reproduction on the
fed through the ?ame gun.
metal base layer 2. An even layer of less than 1 mil
The metals comprising the backing layer 3 are selected
thickness is sufficient. Although nylon is an excellent
adhesive for adhering metal to a model where moderate 20 on the basis of their melting points and ability to metal
lurgically bond to each other, as in brazing, without the
spraying temperatures can be used, it can not be used
use of flux. By my invention I am able to produce a
where hard metals with their correspondingly higher
spray-deposited metallic layer having a tensile strength
melting temperatures are to be sprayed. According to
of 25,000 to 41,000 p.s.i. after it has been heated or sin
my discovery, a ?lm-forming silicate such as sodium
silicate, commercial water glass, will permit adhesion 25 tered at a temperature which is above the melting point
of one of the backing layer metals but below that ofthe
of projected molten metal particles at temperatures as
others and below that of the base layer metal.
high as 2100° F. A typical solution that may be used
In articles or molds where “Nicrobraz” is usedas the
is three parts water glass and one part water. For maxi
base or impression layer, some practical combinations of
mum'adhesion of the silicate ?lm to the model, the model
should be preheated to a temperature above 140° F.
30 metals for use in the backing layer 3 include the follow
ing pairs:
Phosphor-bronze, and self-fluxing silver brazing alloy
containing phosphorus.
Copper, and self-?uxing silver brazing alloy containing
phosphorus.
After application of the adhesive 5, it is dehydrated
by passing hot air over the model through air duct 10,
from a source not shown, and a base layer 2. of a hard
metal having a melting point between 1500° F. and
2100” F., such as an alloy of chrome nickel, is sprayed
over the coated model 4. This base layer 2 takes the
impression 7 from the model. It must do so accurately,
Chrome-copper, and self-?uxing silver brazing alloy con
taining phosphorus.
but, on the other hand, it must also be hard enough to
withstand wear caused by frequent use in molding opera
tions, and if it is on a mold used on rubber stock, it 40
must be inert to the rubber. The selection of metals
used to form the base layer 2 is further restricted by
their spraying temperatures, since the temperature must
be high enough to soften the adhesive 5 covering the
Various steels, with self-?uxing silver brazing alloys con
taining lithium or with self-?uxing copper-nickel braz
ing alloys containing lithium and boron.
Beryllium-copper, with a brazing alloy containing lithium.
Phosphor-bronze, with a self-?uxing copper-phosphorus
brazing alloy.
model 4 but not so high as to break it down, else the 45 A strong deoxidizer, such as phosphorus, tin, cadmium,
particles will bounce off the model and fail to build up.
lithium or boron, is always included in the backing layer,
Where water glass is used as the adhesive, a high-melting
usually as a part of the self-?uxing brazing alloy, to in
metal such as copper can be deposited as a base layer,
sure removal of oxides and other undesirable substances
but, since copper reacts with rubber, it is generally un
formed during sintering (described in a subsequent para
suitable for use in contact with rubber stock. “Nicro 60 graph) of the deposited metals, thus facilitating forma
bra'z,” an alloy consisting of 15% chromium, 4.50%
silicon, 4.00% iron, 3.95% boron and the balance nickel,
tion of a strong metallurgical bond between the sprayed
in powdered form can be sprayed at about 1850'” F. on
a water-glass-coated model. It produces a hard surface,
inert to rubber, with a good reproduction of the model’s 55
surface detail, excellent for the compression molding
of articles. ‘The thickness of the base layer 2' is not
critical, and is determined mostly by the use to' which the
article or mold will be put. A thickness of 0.005 to .010
metal particles by promoting wetting of the surfaces of
the solid state metals by the liquid state metals. The
deoxidizer isa very important feature of my invention.
In order to assure a strong backing layer after sinter'
ing, the self-?uxing brazing alloy is selected to ?t the
characteristics of the other backing layer metals. For
example, a silver brazing alloy with 5% phosphorus, 15%
silver and 80% copper has been found to be an effective
inch of “Nic'robraz” on a mold surface is suflicient to 60 self-?uxing brazing alloy to spray with copper and copper
ensure sharp impressions in the molding of rubber arti
alloys. Self-?uxing brazing alloys containing .5—3%
cles.
nickel, .5—2% lithium and the balance silver, or .5—20%
nickel, .5—2% ‘boron, 15-2% lithium and the balance
copper, are examples of alloys which are effective with
The technique used to obtain the desired thick—
ness is to work the spray gun back and forth over the
article being sprayed, in known manner.
Hot or cold air, as required, is blown over the model 65 ferrous materials, nickel, and nickel alloys.
4 by means of air duct 10 during the flame-spraying
When the desired thickness of backing layer 3 has been
steps to reduce any temperature differences that may
deposited, the model 4 is removed, as by breaking or cut
exist between the model and the molten particles sprayed
ting it out, leaving a metal shell or mold composed of
the base or impression layer 2 and the backing layer 3.
on it and to prevent cracking and breaking of the model,
especially if it is a plaster of Paris model. Heat is also
The composite shell ,1 is then subjected to heat treatment
supplied to the silicate-coated model before the metal
or sintering at a temperature which is above the melting
spraying is started, in order to dehydrate the ?lm of
point of one of the backing layer metals, but is below
water glass, as drying by mere exposure to the atmos
phere is too incomplete to prevent peeling of the silicate
?lm during the metal spraying steps.
that of the others as well as below that of the metal in
the base layer 2. Sintering is generally done in the open
75 atmosphere with the shell packed in charcoal. A reduc
3,053,610
5
ing atmosphere, such as incompletely burned ?ue gases,
Although I have herein speci?cally described only
or hydrogen, or a neutral atmosphere such as dry helium
some of the variations in the invention, it is understood
that the invention is not limited thereby, but is susceptible
may be employed, if desired, but is not essential.
of change in form or detail within its scope.
The thickness of the backing layer 3 is a matter deter
mined by the degree of strength required in the mold,
Having thus described my invention, what I claim and
desire to protect by Letters Patent is:
1. A massive, thick-walled mold suitable for compres
sion molding plastic bodies at high temperatures and pres
which in turn depends on its use. Molds having a
thickness of from 0.1 inch to 3.0 inches have been made
successfully by my method, with no cracking of the
sures comprising
articles.
a base layer of metal conforming on one side faithfully
The mold resulting from the above Process consists 10
in surface detail to a prototype model and compris
of a ?rst or base lamellar layer of metal conforming on
ing coalesced lamellar metallic particles, and
one side faithfully in surface detail to the prototype
a backing layer which is thick relative to said base layer
model and composed of coalesced lamellar, hard metal
and which comprises
lic particles, and a backing layer comprised of a matrix
a matrix of coalesced lamellar particles of a high
of coalesced lamellar particles of a high-melting metal
interspersed uniformly throughout the backing layer with
melting metal, and
a ?ller metal of lower melting point uniformly
?lling the voids in said matrix and metallurgi
cally bonded to the metal of said matrix,
another and lower-melting metal metallurgically bonded
to said higher-melting metal and ?lling the voids therein.
A mold or shell 1 made with a “Nicrobraz” base layer
and a backing layer 3 of Phosphor-bronze and self-?ux
ing silver brazing alloy and sintered at 1350° F. in the 20
said backing layer being characterized by high ten
sile strength, ductility, and freedom from internal
stresses.
open atmosphere was ‘found to have a tensile strength
of 41,000 p.s.i., and to have a 15% elongation at break.
The same kind of molds that had not been sintered broke
2. A mold in accordance with claim 1 in which said
matrix also contains interspersed therethrough a small
percentage of the products of the high-temperature re
action of a deoxidizing element with oxides of the metals
of which the mold is formed.
3. A mold in accordance with claim 1 in which said
high-melting metal of said backing layer is a metal se
lected from the group consisting of Phosphor~bronze al
under tensile stresses of about 5000 psi. with no elonga
tion. The increased strength and ductility are the result
of the metallurgical bond created between the self-?uxing
silver brazing alloy particles and the particles of Phos
phor-bronze by the sintering operation. The metallurgi
cal bond thus achieved is much strong than the mechani 30
loy, chrome-copper alloy, and copper and said low-melt
cal bond of normally sprayed metals.
ing metal is a self-?uxing silver brazing alloy containing
By the method set forth, laminated molds having a
phosphorus.
hard base layer and tough backing layer suitable for
4. A mold in accordance with claim 1 in which said
compression molding as well as slush molding of all
manner of plastic articles may be made, e.g., for the 35 high-melting metal is steel and said low-melting metal is
a self-?uxing brazing alloy containing lithium.
production of golf balls, arm rests, electric plugs for fe
5. A mold in accordance with claim 1 in which said
male receptacles, hardware, pipe ?ttings, gears, handles,
high-melting metal is beryllium-copper and said low-melt
toys, containers, footwear, and myriad other articles.
ing metal is a self-fluxing brazing alloy containing lithium.
For some purposes, such as the production of heavy
6. A mold in accordance with claim 1 in which said
duty molds, it is desirable to surround a laminated spray 40
backing layer has a thickness greater than one-tenth inch.
deposited article, made according to my invention, with
a massive body of cast metal, such as cast aluminum.
References Cited in the ?le of this patent
The casting is suitablly done in known manner after the
spray-deposited metal has been sintered. In this manner
UNITED STATES PATENTS
a massive article may be built up at much less expense 45 1,466,640
Coleman _.__.. _______ __ Aug. 28, 1923
than if the entire article were to be built up by spraying.
2,127,487
Voit _______________ __ Aug. 16, 1938
If desired, further reinforcement and mechanical inter
locking may be provided by screws or bolts embedded
in or extending into both the sprayed shell and the cast
body.
This application is a division of application Serial No.
646,662, ?led March 18, 1957, now Patent No. 2,966,423.
2,288,658
Stossel ________ _._ ____ __ July 7, 1942
2,851,331
2,966,423
Miller ______________ __ Sept. 9, 1958
Shichman ____________ __ Dec. 27, 1960
50
FOREIGN PATENTS
360,743
Great Britain ________ __ Nov. 12, 1931